As I mentioned on another thread, I just finished a road trip from my home near Charleston, WV to NJ, then to DE, on to MD, and back home. On the trip up and back the car was loaded down with 560+ pounds of people and cargo (really stuffed the hatch!). So, it was slightly overloaded...
The car did well enough climbing the Appalachians over and back. I used 4th on the steepest inclines to maintain decent speed. It reminded me of my first car, the 70 hp Nissan Pulsar! I kept the car around 65 mph most of the time and used the A/C about half the time. Of course, there was the obligatory construction backups on various sections, so we spent about 1.5 - 2 hours crawling in traffic and one tank was spent driving in a lot of stop and go sightseeing in DE. I didn't have any problems keeping up with the flow of traffic on I-95 around DC and Baltimore. The car is no Buick on the highway, but it was certainly adequate. Most highways were fine, but some poorly maintained sections or construction areas were kind of jarring. I used premium on all fill ups.
I averaged 43 miles per gallon over the entire trip. Not bad for the conditions and a relatively new engine (1,100 miles on the ODO when we left). However, on the most recent tank of driving back and forth to work after this trip I managed 48.1 mpg. It looks like the engine is breaking in and returning a bit better mileage.